Meta-analysis of association between C-reactive protein and immediate success of electrical cardioversion in persistent atrial fibrillation.

Current evidence links atrial fibrillation (AF) to the inflammatory state. Also, increased C-reactive protein (CRP) levels have been associated with greater risk of recurrence of AF after successful electrical cardioversion (EC). We conducted a meta-analysis of observational studies to examine the association between baseline CRP levels and the immediate success of EC in persistent AF. We searched the literature published November 2007 or earlier. In addition, a manual search was performed using all review articles on this topic, reference lists of studies, and abstracts from conference reports. Of the 342 initially identified studies, 6 prospective observational studies with a combined 366 patients (297 with successful and 69 with failed EC) were analyzed. Overall, CRP levels were greater in patients with failed EC. The standardized mean difference in the CRP levels between patients with successful and those with failed EC was -0.41 units (95% confidence intervals -0.68 to -0.14) and the Z score for overall effect was 2.98 (p=0.003). The heterogeneity test showed that there were no significant differences between the individual studies (p=0.36; I(2)=9.1%). In conclusion, our meta-analysis suggests that increased CRP levels are associated with greater risk of EC failure. CRP assessment before cardioversion may provide prognostic information regarding the success of the procedure.